Abstract

-type conductivity control of In- and N-polar InN layers grown on GaN templates with different Mg concentrations ([Mg]) was systematically investigated by using electrolyte-based capacitance-voltage (ECV) analyses. With increasing [Mg],-type conduction was confirmed for [Mg]s from . The conduction was reversed to type at [Mg]s above , however, due to overdoping effects introducing shallow donors in InN. Further, it was found that charges at the interface states located within forbidden band of InN greatly affected the ECV measurements resulting in overestimation of net acceptor concentrations, and some calibration was necessary to estimate them.

Received 23 September 2007Accepted 22 November 2007Published online 14 December 2007

Acknowledgments:

The authors acknowledge T. Mukai of Nichia Corporation for providing us GaN templates, A. Majima and M. Saitoh of Nanometrics Japan LTD and T. Wolff of WEP LTD for helping ECV measurements. This research was supported in part by the Grant-in-Aid for Scientific Research on Priority Areas, MEXT, 18069002, 2007.